大跨度超宽钢箱梁顶推施工的临时墩布置方案研究

Study on the Layout of Temporary Piers in Jacking Construction of the Steel Box Girder with Long Span and Super Width

大跨度超宽钢箱梁在顶推施工过程中受力复杂,临时墩间距对顶推施工过程的梁体受力性能和安全性影响较大。现以济南齐鲁黄河大桥为工程背景,对钢箱梁顶推施工中,临时墩的布置进行了研究分析。采用大型通用有限元软件,分别建立了钢箱梁的空间杆系模型和局部板壳模型,计算分析不同临时墩布置方案下,钢箱梁的受力特性;得到钢箱梁连续顶推施工过程中,钢梁的应力包络情况;并比较研究临时墩的数量变化时,钢箱梁局部应力的分布情况。计算结果表明:主跨420 m的济南齐鲁黄河大桥钢箱梁顶推施工的合理临时墩间距为70 m。

During the incremental launching construction,the steel box girder with long span and super width was usually with sophisticated behaviors,and the distance between temporary piers had great effect on the mechanical performance and safety of the girder.Taking Jinan Qilu Yellow River Bridge as the engineering background,this paper analyzed the layout of temporary piers in jacking construction of the steel box girder.The mechanical characteristics of the steel box girder under different layout schemes of temporary piers were analyzed with the linkage model and local plate-shell model which were respectively established by large general finite software,and the stress envelope of the steel box girder in continuous jacking construction was obtained,and the distribution of the local stress of the steel box girder was comparatively studied with the variation of numbers of temporary piers.The calculation results showed that the reasonable distance between the temporary piers of the steel box girder of Jinan Qilu Yellow River Bridge with the main span of 420 m was 70 m.